class MyQueue {
    public Stack<Integer>  stack1;
    public Stack<Integer>  stack2;


    public MyQueue() {
        stack1=new Stack<>();
        stack2=new Stack<>();

    }
    
    public void push(int x) {
        //默认压入到栈1中
        stack1.push(x);

    }
    
    public int pop() {
        if(empty()){
            return -1;
        }
            if(stack2.empty()){
                while(!stack1.empty()){
                    stack2.push(stack1.pop());
                }
            }
            return stack2.pop();

    }
    
    public int peek() {
        if(empty()){
            return -1;
        }

       if(stack2.empty()){
                while(!stack1.empty()){
                    stack2.push(stack1.pop());
                }
            }
            return stack2.peek();



    }
    
    public boolean empty() {
        return stack1.isEmpty()&&stack2.isEmpty();

    }
}
